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Don’t Be So Sensitive: Incidents, Accidents, and Near Misses in Lab Research

Safety Partners is thrilled to announce the publication of its 5th edition of 

“Incidents, Accidents, and Near Misses in Laboratory Research.” 

This collection of real life safety lessons has just been mailed to clients and many friends.  Look for it in your (actual) mailbox!

To celebrate this milestone 5th publication, we are sharing a full story here, written by

Kristin Garland, CIH, Associate Director, Industrial Hygiene and QRT at Safety Partners.

Request your copy at [email protected]

Don’t be so sensitive…

Working as a safety officer, I can interact with many laboratory professionals, at all different levels, and people of highly diverse backgrounds. When providing chemical training to clients, one thing I always talk about is chemical sensitivities. Many people don’t realize that some people are inherently more sensitive to chemicals than others [1]. Just as some people have the ability to taste PTC (phenylthiocarbamide — a compound that tastes very bitter to people who possess a certain gene[2]) while others do not, some people will have more severe reactions to certain chemicals than others.

Regulatory and consensus standards for chemical exposures are designed to protect the average healthy adult in the general working population. Therefore, if a person has sensitivity to a chemical, exposure to a “safe” amount of that chemical may cause him or her to have a reaction, while others who do not have the sensitivity will not have a reaction. Unfortunately, there is not currently a way to know if someone has a chemical sensitivity, so most people find out the hard way. These types of sensitivities usually manifest as general allergy or flu-like symptoms [1].

The Mystery

One afternoon, after giving one of my talks on chemical hygiene and mentioning chemical sensitivities, I was approached by a young woman who told me she had been experiencing allergy-like symptoms every Tuesday after work. Without fail, Erica would go to work on Tuesday morning, feeling completely normal, and throughout the day she would begin to develop a scratchy throat, watery eyes, and eventually a runny nose. This seemed peculiar to her and, as she recognized from my talk, it was certainly a pattern!

I began asking her a series of questions to try to help her identify what might be causing these symptoms. I was trying to narrow down what happened on Tuesdays that didn’t happen on other days of the week.

“Do you cook a certain meal or eat at a certain restaurant every Tuesday?”


“Do you take a different form of transportation or travel a different route to and from work on Tuesdays?”


“Do you clean your house only on Tuesdays?”


And on it went…

Alright, so clearly there wasn’t anything unique happening at home that was inducing these symptoms only one day a week.

“Let’s focus on what happens at work.”

The Culprit

When investigating what goes on in the lab and the areas surrounding where Erica works, we discovered that the laboratory next door tends to use beta-mercaptoethanol (BME) on Tuesdays. BME is a widely used chemical in research, but it also has a very distinct and very potent odor­ that most people find unpleasant.  Even very small amounts of it can stink up a lab. For this reason, it is usually used in a fume hood, where the odor will be whisked away rather than diffusing throughout the room. Exposure to working concentrations of BME tends to be an annoyance due to the odor but are not generally considered a major exposure hazard due to the extremely small amounts in use.  Exposure to stock solutions of BME are considered hazardous and appropriate controls must be instituted for its handling.

The lab next door was using BME in conjunction with a large piece of equipment that would not fit in a fume hood. Therefore, they were not using BME in a fume hood. Erica noted that she had experienced some issues with BME previously, but she did not smell it in the lab space she was working in and did not use it herself during the times she had developed these symptoms. However, she did spend a lot of time in the microscope room, which sits between the two lab spaces.

Problem Solved

It turned out that the laboratories and the microscope room shared an HVAC system, which re-circulated the return air through all three lab spaces. So, the BME that was not used in a fume hood in the adjacent lab was circulating in small amounts into Erica’s lab and the microscope room. It turned out that every Tuesday she was being exposed to BME without even knowing it!

To confirm this was the case and to test if the levels of BME in the lab were within the regulated amount, industrial hygiene sampling was performed in all three lab spaces. The only measurable level of BME was found in the lab that was directly using the chemical, and it was well below the established exposure limits. According to this test, the average employee would not experience any adverse effects from exposure to the low levels of chemical.

Regardless of this result, exposure to BME was the only culprit that made sense for causing Erica to have allergy-like symptoms every Tuesday. It seems that Erica had a chemical sensitivity to BME – something she had suspected earlier on, but now felt even more strongly that it was the case.

The lab next door agreed to be more careful in their handling of BME and make sure to use it in the fume hood as much as possible. They also agreed to notify Erica on days when they were using BME, so that she could take extra precautions as to not be exposed. And they all lived happily ever after… but not without learning some lessons first!

Lessons Learned

  • People can be overly sensitive to certain chemicals and it is important to be aware of this phenomenon
  • Just because your sampling data shows that chemical levels are below regulatory limits does not mean that all your employees are properly protected
  • Looking for trends in symptoms can help identify situations in which someone may have a chemical sensitivity
  • Always err on the side of caution when using potentially irritating chemicals and stick to the best practice of use to avoid unnecessary exposures (in this case, using BME in a fume hood)


  1. Martini, A., S. Iavicoli, and L. Corso, Multiple chemical sensitivity and the workplace: current position and need for an occupational health surveillance protocol. Oxid Med Cell Longev, 2013. 2013: p. 351457.
  2. Wooding, S., Phenylthiocarbamide: a 75-year adventure in genetics and natural selection. Genetics, 2006. 172(4): p. 2015-23.
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